cd (command)

cd / chdir
	The cd command illustration (in a shell session in Debian GNU/Linux)
Developer(s)	AT&T Bell Laboratories, MetaComCo, Microsoft, IBM, DR, Novell, HP, JP Software, ReactOS Contributors
Operating system	Unix, Unix-like, V, DOS, MSX-DOS, FlexOS, OS/2, TRIPOS, Windows, MPE/iX, Plan 9, Inferno, ReactOS, KolibriOS, SymbOS
Platform	Cross-platform
Type	Command

cd is a command that changes the working directory – available in many operating system shells and applications that maintain a working directory. In some contexts, the command can perform actions other than change directory. Some environments provide the change directory feature via a different command name such as chdir.

Implementations

Generally, a computer system that provides access to a hierarchical file system, provides a change directory command to set the working directory. As this applies to most operating system shells, most support a change directory command, including Unix and Unix-like (i.e. Linux) shells, and Microsoft shells including Command Prompt and PowerShell.

Other operating systems with shells supporting the command include OS/2,^[1] TRIPOS,^[2] AmigaOS^[3] (where the command is implied for an input path), ReactOS,^[4] DOSBox, and UEFI.^[5]

On MS-DOS, the command is available in version 2 and later^[6]
DR DOS 6.0 includes the command as both cd and chdir^[7]
On HP MPE/iX the command is chdir^[8]
On OpenVOS, the command is change_current_dir^[9]

Unlike many shell commands that are implemented as separate applications, change directory is often built-in to the shell because it affects the state of the shell whereas other commands modify system state outside the shell. If the command was implemented as a separate application, then the child process would need to modify state in the parent process, but this is often prevented for safety. The command is built-in for most Unix shells (Bourne, tcsh, Bash, etc.), Windows Command Prompt and PowerShell, and MS-DOS COMMAND.COM.

In a shell, the change directory command is typically implemented via a system call which on Unix and Unix-like systems is typically POSIX chdir() and on Windows is in the Windows API.

The command is also provided in many programs other than shells. In the File Transfer Protocol, the control stream command is CWD, but the functionality is available as cd in most command-line clients and some also provide lcd for changing the local working directory vs. the remote setting. The numerical computing environments MATLAB and GNU Octave include a change directory command as cd.^[10]^[11]

Usage

A directory is a logical section of a file system used to hold files. Directories may also contain other directories. The cd command can be used to change into a subdirectory, move back into the parent directory, move all the way back to the root directory or move to any given directory.

Consider the following subsection of a Unix filesystem, which shows a user's home directory (represented as ~) with a file, text.txt, and three subdirectories.

A user's view of the file system in Unix-like systems begins with the home directory (often abbreviated to `~`). From there, the tree can spread into more subdirectories and/or files.

If the user's current working directory is the home directory (~), then entering the command ls followed by cd games might produce the following transcript:

user@wikipedia:~$ ls
workreports games encyclopedia text.txt
user@wikipedia:~$ cd games
user@wikipedia:~/games$

The user is now in the "games" directory.

A similar session in DOS (though the concept of a "home directory" may not apply, depending on the specific version^[vague]) would look like this:

C:\> dir
workreports        <DIR>       Wed Oct 9th   9:01
games              <DIR>       Tue Oct 8th  14:32
encyclopedia       <DIR>       Mon Oct 1st  10:05
text        txt           1903 Thu Oct10th  12:43
C:\> cd games
C:\games>

DOS maintains separate working directories for each lettered drive, and also has the concept of a current working drive. The cd command can be used to change the working directory of the working drive or another lettered drive. Typing the drive letter as a command on its own changes the working drive, e.g. C:; alternatively, cd with the /d switch may be used to change the working drive and that drive's working directory in one step. Modern versions of Windows simulate this behaviour for backwards compatibility under CMD.EXE.^[12]

Note that executing cd from the command line with no arguments has different effects in different operating systems. For example, if cd is executed without arguments in DOS, OS/2, or Windows, the current working directory is displayed (equivalent to Unix pwd). If cd is executed without arguments in Unix, the user is returned to the home directory.

Executing the cd command within a script or batch file also has different effects in different operating systems. In DOS, the caller's current directory can be directly altered by the batch file's use of this command. In Unix, the caller's current directory is not altered by the script's invocation of the cd command. This is because in Unix, the script is usually executed within a subshell.

Options

Unix, Unix-like

cd by itself or cd ~ will always put the user in their home directory.
cd . will leave the user in the same directory they are currently in (i.e. the current directory won't change). This can be useful if the user's shell's internal code can't deal with the directory they are in being recreated; running cd . will place their shell in the recreated directory.
cd ~username will put the user in the username's home directory.
cd dir (without a /) will put the user in a subdirectory; for example, if they are in /usr, typing cd bin will put them in /usr/bin, while cd /bin puts them in /bin.
cd .. will move the user up one directory. So, if they are /usr/bin/tmp, cd .. moves them to /usr/bin, while cd ../.. moves them to /usr (i.e. up two levels). The user can use this indirection to access subdirectories too. So, from /usr/bin/tmp, they can use cd ../../local to go to /usr/local
cd - will switch the user to the previous directory. For example, if they are in /usr/bin/tmp, and go to /etc, they can type cd - to go back to /usr/bin/tmp. The user can use this to toggle back and forth between two directories without pushd and popd.

DOS, OS/2, Windows, ReactOS

no attributes print the full path of the current directory.
-p Print the final directory stack, just like dirs.
-n Entries are wrapped before they reach the edge of the screen.
-v entries are printed one per line, preceded by their stack positions.
cd\ (DOS and Windows only) returns to the root dir. Consequently, command cd\subdir always takes the user to the named subdirectory on the root directory, regardless of where they are located when the command is issued.

References

^ "JaTomes Help – OS/2 Commands". www.jatomes.com. Archived from the original on 2019-04-14. Retrieved 2019-08-11.
^ "Introduction to Tripos" (PDF). Retrieved 2020-05-01.
^ Rügheimer, Hannes; Spanik, Christian (May 1, 1988). AmigaDOS quick reference. Grand Rapids, Mi : Abacus. ISBN 9781557550491 – via Internet Archive.
^ "Reactos/reactos". GitHub. 3 January 2022.
^ "EFI Shells and Scripting". Intel. Retrieved 2013-09-25.
^ Wolverton, Van (2003). Running MS-DOS Version 6.22 (20th Anniversary Edition), 6th Revised edition. Microsoft Press. ISBN 0-7356-1812-7.
^ "DR DOS 6.0 User Guide Optimisation and Configuration Tips" (PDF). Archived from the original (PDF) on 2019-09-30. Retrieved 2019-08-13.
^ "MPE/iX Command Reference Manual" (PDF). Archived from the original (PDF) on 2018-10-21. Retrieved 2018-10-21.
^ "OpenVOS Commands Reference Manual" (PDF). stratadoc.stratus.com. Retrieved 2020-09-12.
^ "Change current folder – MATLAB cd". www.mathworks.com.
^ "Function Reference: cd". octave.sourceforge.io.
^ "October 11, 2010". The Old New Thing.

External links

Windows XP > Command-line reference A-Z > Chdir (Cd) from Microsoft TechNet
cd: change the working directory – Shell and Utilities Reference, The Single UNIX Specification, Version 4 from The Open Group

[1] "JaTomes Help – OS/2 Commands". www.jatomes.com. Archived from the original on 2019-04-14. Retrieved 2019-08-11.

[2] "Introduction to Tripos" (PDF). Retrieved 2020-05-01.

[3] Rügheimer, Hannes; Spanik, Christian (May 1, 1988). AmigaDOS quick reference. Grand Rapids, Mi : Abacus. ISBN 9781557550491 – via Internet Archive.

[4] "Reactos/reactos". GitHub. 3 January 2022.

[EFI-Shells-and-Scripting-5] "EFI Shells and Scripting". Intel. Retrieved 2013-09-25.

[RUNNINGMSDOS-6] Wolverton, Van (2003). Running MS-DOS Version 6.22 (20th Anniversary Edition), 6th Revised edition. Microsoft Press. ISBN 0-7356-1812-7.

[drdos6userguide-7] "DR DOS 6.0 User Guide Optimisation and Configuration Tips" (PDF). Archived from the original (PDF) on 2019-09-30. Retrieved 2019-08-13.

[8] "MPE/iX Command Reference Manual" (PDF). Archived from the original (PDF) on 2018-10-21. Retrieved 2018-10-21.

[9] "OpenVOS Commands Reference Manual" (PDF). stratadoc.stratus.com. Retrieved 2020-09-12.

[10] "Change current folder – MATLAB cd". www.mathworks.com.

[11] "Function Reference: cd". octave.sourceforge.io.

[12] "October 11, 2010". The Old New Thing.

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v t e Unix command-line interface programs and shell builtins
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Categories Standard Unix programs Unix SUS2008 utilities List